KR100443901B1 - Thin film transistor type photo sensor and method for fabricating the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive device, which aims to maximize the capacity of a window and storage capacitor through which light is transmitted by designing a first electrode of a storage capacitor in a predetermined method.

According to an aspect of the present invention, there is provided a thin film transistor type photosensitive device, comprising: a storage capacitor including a first storage electrode, the first storage electrode, and a second storage electrode; A switching thin film transistor including a switch source electrode and a drain electrode formed on one side of the switch gate electrode and the switch source wiring, and for controlling the emission of charge accumulated in the storage capacitor; It receives light to generate a photocurrent to supply charge to the storage capacitor, and includes a sensor drain electrode and a sensor source electrode formed on one side of the sensor gate electrode and the sensor drain wiring, the channel width is substantially the width of the switch source wiring and the A sensor thin film transistor including a sensor drain wiring and a portion other than a spaced portion between the switch source wiring and the sensor drain wiring and the second storage electrode; A thin film transistor type photosensitive device including a window through which light is transmitted is disclosed.

Description

Thin film transistor type photo sensor and its manufacturing method {Thin film transistor type photo sensor and method for fabricating the same}

The present invention relates to a photosensitive device using a thin film transistor and a method of manufacturing the same, and more particularly, to a storage capacitor for storing charge in a thin film transistor type photosensitive device.

In general, a photo sensor is used as an image reader in an image processing apparatus such as a facsimile or a digital copying machine.

In addition, as the information age has evolved, it has been applied to a fingerprint reader, which is a recognition device for identifying and recognizing individuals.

The photosensitive device used as the image reader is a device that receives light from an internal light source, stores charges according to the intensity of light reflected on a subject, and outputs the stored charges to the outside through a driving circuit.

As described above, the photosensitive device operating by receiving light may use a thin film transistor. In this case, the semiconductor layer of the thin film transistor used as the sensing unit of the photosensitive device may use amorphous silicon. This is because amorphous silicon is sensitive to light. Such amorphous silicon has electrical properties of low dark electrical conductivity and high photoelectric conductivity.

When light is incident on amorphous silicon, carriers of electron-hole pairs are generated internally, and thus the resistivity of the amorphous silicon layer is reduced to allow current to flow.

As described above, a device using the electrical properties in the dark state and the optical state of amorphous silicon is a thin film transistor type photosensitive device.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the general thin film transistor type photosensitive device.

1 is a plan view of one pixel of a general thin film transistor type photosensitive device. As shown in FIG. 1, the main configuration of the thin film transistor type photosensitive device includes a window 8 that receives light from a lower light source on a substrate, and receives light entering through the window 8. A reflective object (not shown) is positioned on the photosensitive device 100, and a light sensing thin film transistor 6 for generating current by sensing light reflected from the subject is positioned.

The photocurrent flowing through the photosensitive thin film transistor 6 (hereinafter referred to as a sensor thin film transistor) is accumulated in the storage capacitor 4 and the charge stored in the storage capacitor 4 is a thin film transistor 2, which serves as a switching. By a switching thin film transistor) to an external driving circuit (not shown). In addition, in the switching thin film transistor 2, a separate light blocking film 9 is disposed on the semiconductor layer to block light.

Since the photosensitive device 100 has a structure for sensing light reflected from a subject by receiving light, a window 8 occupying an area of a predetermined size or more is essential.

In addition, since the storage capacitor 4, which is a means for storing the photocurrent generated by the intensity of light reflected by the subject, must also maintain a predetermined capacity, this also occupies a predetermined area. The storage capacitor 4 includes a first storage electrode 30, a second storage electrode 34, and a storage wiring 30 ′ connected to the first storage electrode 30.

Meanwhile, referring to FIG. 2, which is a cross-sectional view taken along line II-II 'in a plan view of one pixel of FIG. 1, first, a switching thin film transistor 2 and a storage capacitor 4 sensor thin film transistor on a substrate 1 are described. In the region (6), the first metal layers 20 and 30 and 40 are respectively located. The first metal layer includes a switch gate electrode 20, a first storage capacitor 30, and a sensor gate electrode 40.

In addition, the insulating layer 32 is disposed on the first metal layer 20, 30, 40, and the switching thin film transistor portion 2 is deposited and patterned on the insulating layer 32 by containing amorphous silicon and impurities. ) And the sensor semiconductor layer 26 and the sensor semiconductor layer 46 are formed in the sensor thin film transistor portion 6, respectively.

In addition, the second metal layer is deposited and patterned so that the switch source and drain electrodes 22 and 24 of the switching thin film transistor 2 and the second storage electrode 34 of the storage capacitor portion 4 and the sensor thin film transistor portion ( The sensor source and drain electrodes 42 and 44 of 6) are formed. The insulating film 16 and the protective layer 10 are formed to protect the switching thin film transistor 2 and the storage capacitor 4 sensor thin film transistor 6, which are components of each photosensitive device, from moisture or external impurities. do. In this case, the insulating layer 16 and the protective layer 10 use an inorganic insulating layer or an organic insulating layer. That is, an inorganic insulating film uses a silicon nitride film (SiN _x ), a silicon oxide film (SiO ₂ ), or the like, and BCB, acrylic, or the like is used as an organic insulating film.

Since the sensor thin film transistor 6 operates by a photocurrent caused by light in an off state, a negative voltage is always applied to the sensor gate electrode 40 to maintain the off state.

In addition, the photocurrent generated by the light flows through the sensor source electrode 42 of the sensor thin film transistor 6 to the second storage electrode 34 of the storage capacitor 4 and is stored in the storage capacitor 4.

In addition, when an externally controlled bias voltage is applied to the gate electrode 20 of the switching thin film transistor 2, the charge stored in the storage capacitor 4 is switched through the switch drain electrode 24 of the switching thin film transistor 2. To 22.

An important factor on the light efficiency of the sensor thin film transistor is the amount of light transmitted through the window 8.

In addition, the signal-to-noise ratio (S / N) needs to be large for smooth operation of the photosensitive device, that is, to obtain a clear image.

In addition, the photocurrent generated in the sensor thin film transistor should be large, and the switching operation of the switching thin film transistor should be fast.

However, in the conventional photosensitive device, the storage wiring 30 ′ for supplying power to the storage capacitor 4 is formed at the first storage electrode 30 constituting the storage capacitor 4, thereby providing a lower light source. It covers the area where light is transmitted. As a result, the area of the window 8 is reduced to reduce the amount of light incident on the sensor thin film transistor 6.

In addition, the capacitance of the storage capacitor 4 is reduced by the storage wiring 30 ′, thereby reducing the S / N ratio. As a result, the sensing ability of the photosensitive device is degraded, and a desired image cannot be obtained.

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention aims to simplify the structure of a storage capacitor.

In addition, in the thin film transistor type photosensitive device, the purpose is to improve the signal-to-noise ratio (S / N) by increasing the photocurrent generated in the sensor thin film transistor.

It is also an object to improve the speed of switching the charge stored in the storage capacitor.

In addition, the object is to improve the signal-to-noise ratio by increasing the area of the light transmitting window.

Another object of the present invention is to increase the capacitance of the storage capacitor by changing the design of the first storage electrode.

1 is a plan view showing one pixel of a conventional photosensitive device.

FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. 1. FIG.

3 is a plan view showing one pixel of the photosensitive device fabricated in accordance with the first embodiment of the present invention;

Figures 4a to 4d is a process diagram showing the manufacturing process of the cross-section cut section IV-IV 'of Figure 3 produced according to the first embodiment of the present invention.

5 is a plan view showing one pixel of a photosensitive device fabricated in accordance with a second embodiment of the present invention.

6 is a cross-sectional view taken along the line VI-VI ′ of FIG. 5.

<Explanation of symbols for main parts of drawing>

1: Glass 170: Switch Gate Wiring

180: sensor gate wiring 182: switch source wiring

184: sensor drain wiring 102: switch gate electrode

104: first storage electrode 106: sensor gate electrode

108: first insulating film 110a: switch semiconductor layer

110b: sensor semiconductor layer 114: switch source electrode

116: switch drain electrode 118: second storage electrode

120: sensor source electrode 122: sensor drain electrode

124: second insulating film 126: light shielding film

128: protective layer A: switching thin film transistor

B: storage capacitor C: sensor thin film transistor

In order to achieve the above object, a first embodiment of the present invention includes: a switching gate electrode and a sensor gate electrode formed in parallel to be spaced apart from each other by a predetermined distance; A first storage electrode extending from the sensor gate electrode and having a predetermined area; Source and drain wiring crossing the gate electrodes and spaced apart from each other by a predetermined distance; A switching source electrode branching from the source wiring and partially overlapping with the switching gate electrode; A sensor drain electrode branching from the drain wiring and partially overlapping with the sensor gate electrode; A second storage electrode partially overlapping the switching gate electrode to form a switching drain electrode, and overlapping a sensor gate electrode to form a sensor source electrode, the second storage electrode corresponding to the storage first electrode; A thin film transistor type photosensitive device is disclosed in which a width of a channel of a switching and sensor thin film transistor is defined as a remaining portion except for a spaced portion between the second storage electrode and the source and drain wirings. The second storage electrode may be smaller than the first storage electrode in a width direction of the channel. The second storage electrode may further include a window through which light passes.

In addition, a second embodiment of the present invention includes a storage capacitor including a first storage electrode and a second storage electrode formed smaller than the first storage electrode and accumulating charge; A switching thin film transistor including a switch source electrode and a drain electrode formed on one side of the switch gate electrode and the switch source wiring, and for controlling the emission of charge accumulated in the storage capacitor; It receives light to generate a photocurrent to supply charge to the storage capacitor, and includes a sensor drain electrode and a sensor source electrode formed on one side of the sensor gate electrode and the sensor drain wiring, the channel width is substantially the width of the switch source wiring and the A sensor thin film transistor including a sensor drain wiring and a portion other than a spaced portion between the switch source wiring and the sensor drain wiring and the second storage electrode; A thin film transistor type photosensitive device including a window through which light is transmitted is disclosed.

In addition, the present invention and the window for transmitting light; A sensor thin film transistor including a sensor gate wiring and a gate electrode formed on one side of the gate wiring, and generating a photocurrent by light passing through the window; A storage capacitor including a first storage electrode and a second storage electrode electrically connected to the sensor gate wiring, and storing the photocurrent generated by the sensor thin film transistor in the form of a charge; A thin film transistor type photosensitive device including a switching thin film transistor for controlling emission of charge stored in the storage capacitor is disclosed.

The sensor gate wire and the first storage electrode may be made of the same metal.

The sensor gate electrode and the first storage electrode may have the same potential difference.

In addition, the present invention includes the steps of providing a substrate; Forming a switch gate electrode and a sensor gate electrode of a first metal layer on the substrate, and a first storage electrode to be in electrical contact with the sensor gate electrode; Depositing a first insulating film on the first metal layer and the substrate; Forming a switch and a sensor semiconductor layer on the switch and the sensor gate electrode, respectively; Forming a second storage electrode on the semiconductor layer to be electrically connected to the switch source / drain electrode and the sensor source / drain electrode of the second metal layer, and the switch drain electrode and the sensor source electrode; Forming a second insulating film on the second metal layer and the substrate; Forming a light shielding film on a second insulating film on the switch semiconductor layer; A method of manufacturing a thin film transistor-type photosensitive device including forming a protective film on the light blocking film and the substrate is disclosed.

The first storage electrode may be the same metal layer as the sensor gate electrode.

Hereinafter, the configuration and operation according to the embodiments of the present invention will be described with reference to the accompanying drawings.

First embodiment

3 is a plan view illustrating one pixel of the thin film transistor type photosensitive device according to the first exemplary embodiment of the present invention, and FIG. 4 is a process diagram illustrating a cross section taken along the line IV-IV ′ of FIG. 3. .

First, referring to FIG. 3, the switching thin film transistor E is formed on one side of the pixel on the substrate, and the sensor thin film transistor G is formed along the side facing the switching thin film transistor E. FIG. In addition, the storage capacitor F is formed between the switching thin film transistor E and the sensor thin film transistor G. A window H for receiving light is formed adjacent to the sensor thin film transistor. A general photosensitive device uses a transparent glass substrate because it is a structure that transmits light.

Each component of FIG. 3 will be described in detail according to the configuration thereof.

First, referring to the configuration of the switching thin film transistor E, the gate insulating film and the semiconductor layer 52b are formed on the switch gate electrode 60 and not shown thereon, and the second storage electrode 62 and The connected switch drain electrode 84 and the switch source electrode 82 in contact with the source wiring 80 connected to the external driving circuit are formed. In order to smoothly switch the photosensitive device, the switching thin film transistor E is configured to increase the channel width.

In addition, the sensor thin film transistor G includes a sensor gate electrode 50, a semiconductor layer 52a, a sensor drain electrode 72 connected to the drain wiring 70, and a sensor source electrode 74.

The storage capacitor F includes a first storage electrode 64 connected to the sensor gate electrode 50, a dielectric material (not shown), and a second storage electrode 62 disposed thereon to charge a photocurrent. Save in the form of. That is, image information of the subject is stored. The sensor thin film transistor G is configured to increase the channel width in order to smoothly operate the photosensitive device and generate a large number of photocurrents.

Referring to FIGS. 4A to 4D, which are process diagrams illustrating a process of a cross section taken along cut line IV-IV ′ of FIG. 3, first, as shown in FIG. 4A, a metal layer is deposited and patterned on the substrate 1 to form a switching thin film. A first metal layer is formed such as the switch gate electrode 60 of the transistor portion E, the first storage electrode 64 of the storage capacitor portion F, the sensor gate electrode 50 of the sensor thin film transistor portion G, and the like. . In this case, the metal used as the first metal layer may be chromium (Cr), molybdenum (Mo), aluminum (Al) alloy, titanium (Ti), tin (Sn), tungsten (W), copper (Cu) and the like. have.

4B is a step of depositing a semiconductor layer on the first metal layer. First, an insulating film 92, amorphous silicon, and amorphous silicon containing impurities are successively deposited to a predetermined thickness, respectively, and the switch semiconductor layer 52b and The sensor semiconductor layer 52a is formed.

In this case, the insulating film 92 of the sensor thin film transistor G and the switching thin film transistor E is called a gate insulating film, and the insulating film 92 on the first storage electrode 64 of the storage capacitor part F is a dielectric material. do. The insulating film 92 is an inorganic insulating film such as a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ), but in some cases, an organic insulating film such as benzocyclobutene (BCB) or acryl is used.

Next, as a second metal layer is formed, the switch source electrode 82 and the switch drain electrode 84 of the switching thin film transistor E and the second storage electrode 62 of the storage capacitor F, as shown in FIG. 4C. ) And the sensor source electrode 74 and the sensor drain electrode 72 of the sensor thin film transistor G are formed. The second metal layer may be chromium (Cr), molybdenum (Mo), aluminum (Al) alloy, titanium (Ti), tin (Sn), tungsten (W), copper (Cu) and the like.

After the patterning of the second metal layer, the protective layer 94 is formed to protect the devices E, F, and G formed thereunder from external impurities or impacts.

After the protective layer 94 is formed, a light shielding film 96 is formed on the switching thin film transistor E to prevent the switching thin film transistor E from being degraded by external light (FIG. 4D). ).

The protective layer 94 is an inorganic insulating film such as a silicon nitride film and a silicon oxide film, or an organic insulating film such as BCB, acrylic or the like is used in some cases. As the light shielding film 96, metals such as chromium (Cr), molybdenum (Mo), aluminum (Al) alloy, titanium (Ti), tin (Sn), tungsten (W), and copper (Cu) are used.

Although not shown, after the light shielding film 96 is formed, a protective layer is finally deposited and planarized to protect the devices E, F, and G. In order to protect the devices E, F, and G, an inorganic insulating film such as a silicon nitride film and a silicon oxide film, Therefore, an organic insulating film such as BCB, acrylic or the like is used.

As described above, in the case of forming the photosensitive device according to the first embodiment of the present invention, the channel width of the sensor thin film transistor G and the switching thin film transistor E of the photosensitive device is increased due to the increase in the channel width. The amount of current flowing along this increases. Accordingly, the switching thin film transistor E increases the current in the on state and increases the field effect mobility, thereby improving the switching speed, and the sensor thin film transistor G detects light. By increasing the area and the area forming the current, a large amount of photocurrent can be formed. Therefore, the signal-to-noise ratio can be increased with the improvement of the operation speed.

In addition, since the area of the window (H) for receiving light is increased, the image can be detected even by the weak light of the light source, so that selection of the light source does not require the use of a special light source.

Second embodiment

The first embodiment of the present invention discloses an optical sensing device having a structure that facilitates generation of photocurrent by adjusting a width of a sensor thin film transistor channel. The purpose is to extend the window area to remove and transmit light.

In addition, the present invention is to increase the capacitance of the storage capacitor by introducing a design of a new structure compared to the conventional photosensitive device to form a storage capacitor.

Hereinafter, a thin film transistor type photosensitive device according to a second exemplary embodiment of the present invention will be described in detail with reference to FIGS. 5 and 6.

FIG. 5 is a plan view illustrating a sensor thin film transistor portion of a thin film transistor type photosensitive device according to a second exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along the line VI-VI ′ of FIG. 5.

First, referring to FIG. 5, a switch gate electrode 102 is connected to the switch gate wiring 170 and the switch gate wiring 170. The switch gate electrode 102 is formed wide to block the light coming from the lower light source. If the switch gate electrode 102 is not formed wide, the light from the lower light source (not shown) and the light reflected from the subject (not shown) are combined to reduce the signal-to-noise ratio, thereby reducing image distortion. This may result in intensification.

On the other hand, the switch semiconductor layer 110a is positioned on the switch gate electrode 102. In addition, a switch source electrode 114 is formed on one side of the switch source wiring 182 and the switch source wiring 182.

In addition, a sensor gate electrode 106 is formed on the sensor gate line 180 and one side thereof, and a first storage electrode 104 electrically connected to the sensor gate line 180 is formed. Substantially, the sensor gate wiring 180 and the first storage electrode 104 are formed in the same pattern of the same metal.

The sensor semiconductor layer 110b is formed on the sensor gate electrode 106, and the sensor drain wire 184 and the sensor drain electrode 122 formed on one side thereof overlap with the sensor semiconductor layer 110b. do.

In addition, the second storage electrode 118 is formed to be electrically coupled with the switch drain electrode 116 and the sensor source electrode 120, and overlaps the first storage electrode.

The sensor drain wiring 184, the sensor drain / source electrodes 122 and 120, the second storage capacitor 118, the switch source wiring 182 and the switch source / drain electrodes 114 and 116 are formed of the same metal layer. .

Hereinafter, a manufacturing process of a thin film transistor type photosensitive device according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 6.

First, a gate pattern is formed. Depositing and patterning a first metal layer on the substrate 1 to form a first storage capacitor 104 in electrical contact with the switch gate electrode 102, the sensor gate electrode 106, and the sensor gate electrode 106. do.

Next, after depositing a first insulating film 108 on the first metal layer and the substrate 1 and sequentially depositing amorphous silicon and amorphous silicon containing impurities, the switch gate and sensor gate electrodes 102 and 106. The switch semiconductor layer 110a and the sensor semiconductor layer 110b are formed on the first insulating film 108 on the upper side of the substrate.

The next process is to form an electrode, wherein the switch source electrode 114, the switch drain electrode 116, the sensor drain electrode 122, and the sensor source electrode 120 are formed of the second metal layer. In addition, a second storage electrode 118 connected to the sensor source electrode 120 and in contact with the switch drain electrode 116 is formed on the first storage electrode 104.

In addition, a second insulating film 124 for protecting each element described above is formed on the second metal layer. The second insulating layer 124 is to protect the device from external impact, impurities, moisture, or the like. In addition, it serves as an interlayer insulator for insulating the light-shielding film 126 to be formed later and the device.

Finally, by forming the light shielding film 126 of the third metal layer on the second insulating film on the switch semiconductor layer 110a, and forming the protective layer 128 on the light shielding film 126, It is composed.

The function of the thin film transistor type photosensitive device will be described briefly as follows.

First, when light is incident on the semiconductor layer 110b of the sensor thin film transistor C, a photocurrent is generated in the sensor thin film transistor C. The photocurrent generated in the sensor thin film transistor C flows to the second storage electrode 118 through the sensor source electrode 120 and is stored in the storage capacitor B in the form of charge. The charge stored in the storage capacitor B flows to the switch source electrode 114 through the switch drain electrode 116 of the switching thin film transistor A, and is discharged to an external driving circuit.

Comparing FIG. 6, which is a cross-sectional view of the second embodiment of the present invention, and FIG. 4D, which is a cross-sectional view of the first embodiment, the configuration is very similar, but may vary according to the cutting direction of the plan view.

That is, in the first embodiment, the switching thin film transistors, the storage capacitors, the sensor thin film transistors, and the windows are arranged in order, whereas the second embodiment is arranged in the order of the switching thin film transistors, the storage capacitors and the windows, and the sensor thin film transistors.

As described above, when the thin film transistor-type photosensitive devices according to the first and second embodiments of the present invention are manufactured, the following effects are obtained.

First, when fabricating an optical sensing device according to the first embodiment of the present invention, by increasing the channel widths of the sensor thin film transistor and the switching thin film transistor, the sensor thin film transistor can generate a large amount of photocurrent, and the switching thin film transistor also has a large The on-current increases the switching speed and has the advantage that the photo-sensing device can operate quickly.

Second, in the case of the first embodiment of the present invention, a large amount of photocurrent can be generated even by a weak lower light source, so that selection of light sources is easy.

Third, in the first embodiment of the present invention, the signal-to-noise ratio (S / N) is increased due to the large amount of photocurrent generated in the sensor thin film transistor, thereby obtaining a clear image.

Fourth, when fabricating the photosensitive device according to the second embodiment of the present invention, the structure of the array substrate can be simplified by removing the storage wiring formed on the first storage electrode and supplying power.

Fifth, in the second embodiment of the present invention, there is an advantage that the area of the removed storage wiring can be dedicated to the area of the window or the storage capacitor.

Sixth, in the second embodiment of the present invention, the first storage electrode is shared with the sensor gate electrode to increase the capacitance of the storage capacitor, thereby increasing the signal-to-noise ratio (S / N).

Claims (10)

A switching gate electrode and a sensor gate electrode formed in parallel to be spaced apart from each other by a predetermined distance; A first storage electrode extending from the sensor gate electrode and having a predetermined area; Source and drain wiring crossing the gate electrodes and spaced apart from each other by a predetermined distance; A switching source electrode branching from the source wiring and partially overlapping with the switching gate electrode; A sensor drain electrode branching from the drain wiring and partially overlapping with the sensor gate electrode; A second storage electrode partially overlapping the switching gate electrode to form a switching drain electrode, and overlapping a sensor gate electrode to form a sensor source electrode, the second storage electrode corresponding to the storage first electrode; The thin film transistor type photo-sensing device, characterized in that the width of the channel of the switching and sensor thin film transistor is defined as the remaining portion except the spaced portion between the second storage electrode and the source and drain wiring. The method according to claim 1, And the second storage electrode is smaller than the first storage electrode in a width direction of a channel. The method according to claim 1, And a window through which light passes under the sensor drain electrode. A window that transmits light; A sensor thin film transistor including a sensor gate wiring and a gate electrode formed on one side of the gate wiring, and generating a photocurrent by light passing through the window; A storage capacitor including a second storage electrode and a first storage electrode formed of the same material as the sensor gate wiring and extending from the sensor gate wiring, and storing the photocurrent generated by the sensor thin film transistor in the form of a charge; Switching thin film transistor for controlling the emission of the charge stored in the storage capacitor Thin film transistor type photosensitive device comprising a. The method according to claim 4, The sensor gate wiring and the first storage electrode are thin film transistor type photosensitive device, characterized in that the potential difference is the same. Board; A first storage electrode extending from the switch gate electrode, the sensor gate electrode, and the sensor gate electrode of the first metal layer formed on the substrate; A first insulating film formed on the first metal layer and the substrate; A switch and sensor semiconductor layer respectively formed on a first insulating film on the switch and sensor gate electrode; A second storage electrode connected to a switch source / drain electrode and a sensor source / drain electrode of the second metal layer formed on the semiconductor layers, the switch drain electrode, and the sensor source electrode; A second insulating film formed on the second metal layer and the substrate; A light shielding film formed on the second insulating film on the switch semiconductor layer; A protective film formed on the light shielding film and the substrate Thin film transistor type photosensitive device comprising a. The method according to claim 6, And the sensor gate electrode and the first storage electrode have the same potential difference. Providing a substrate; Forming a switch gate electrode and a sensor gate electrode of a first metal layer on the substrate, and a first storage electrode extending from the sensor gate electrode and substantially of the same material as the sensor gate electrode; Depositing a first insulating film on the first metal layer and the substrate; Forming a switch and a sensor semiconductor layer on the switch and the sensor gate electrode, respectively; Forming a second storage electrode on the semiconductor layer to be electrically connected to the switch source / drain electrode and the sensor source / drain electrode of the second metal layer, and the switch drain electrode and the sensor source electrode; Forming a second insulating film on the second metal layer and the substrate; Forming a light shielding film on a second insulating film on the switch semiconductor layer; Forming a protective film on the light blocking film and the substrate Method for manufacturing a thin film transistor-type photosensitive device comprising a. The method according to claim 8, And the sensor gate electrode and the first storage electrode have the same potential difference. delete